Separating Distance for Overlapping Flat Parcels in a Vertical Position

ABSTRACT

An apparatus for separating overlapping parcels in a vertical position has separating sections arranged along a transport path immediately behind one another, and a drive controller for the separating sections. Drives of those separating sections, in which the most advanced upstream parcel is located are stopped immediately as soon as its front edge is detected in a reception position and a slip-free further transport is securely guaranteed. Number and length of the separating sections are selected in accordance with the range of parcel lengths and the rated transport speed so that a subsequent parcel located at a minimum gap distance is not yet located in the upstream rearmost stopped separating section. The drive of each stopped separating section is started again as soon as the rear edge of the preceding parcel has left this separating section or as soon as the subsequent parcel is located before a free separating section.

The invention relates to a separating distance for overlapping flatparcels in a vertical position in accordance with the preamble of claim1.

Single-stage (U.S. Pat. No. 3,372,925, U.S. Pat. No. 2,941,653) andmultistage (U.S. Pat. No. 6,135,441 A) separating devices are known.With multistage separating devices the individual stages of theseparating device are separated spatially from each other. These arebelt drive groups arranged separately after one another (U.S. Pat. No.6,135,441 A).

The device known from U.S. Pat. No. 2,941,653 known comprises aseparating section, in which the parcels are also accelerated and anacceleration section in which the parcels are further accelerated, andin which in addition in the case of a double transport one of theparcels is removed.

Transferring parcels between two transport sections over a transfer gapat different transport speeds is known from FR 2 657 857 A1.

The way in which parcels can be passed between two transport sections atdifferent transport speeds without a transfer gap is known from U.S.Pat. No. 3,372,925, U.S. Pat. No. 2,941,653 and U.S. Pat. No. 1,858,320respectively. In this context, arranging individually supporteddeflection rollers of the transport belts of two adjacent transportsections alternating in height on a common axis is known from U.S. Pat.No. 3,372,925 and from U.S. Pat. No. 1,858,320.

The position of the parcels is monitored in these known devices with theaid of light barriers. With these solutions it is difficult to separateparcels in a wide range of lengths with high throughput and whilekeeping the load imposed to a low level.

A separating distance described in U.S. Pat. No. 6,550,764 B2 featurestwo separately driven separating sections, but which are far enough awayfrom each other for even the large parcels not to be able to be locatedsimultaneously in both separating section during transport. A receptionpoint is also arranged here after each separating section. Theseparating sections thus do not act jointly on a parcel or a doubleextraction.

In addition a separating section is known from DE 102 12 024 Al with twoseparating sections following directly after one another, which howeverare not separately controllable.

The object of the invention is to create a separating distance foroverlapping flat parcels in a vertical position with which the parcelscan also be separated in a large range of lengths with high-throughputsat low loads.

In accordance with the invention the object is achieved by the featuresof claim 1.

In this case the drive control for the separating sections is designedso that the drive of those separating sections, in which the mostadvanced upstream parcel is located in each case are stopped immediatelyas soon as its front edge is detected in the reception position and alargely slip-free further transport is securely guaranteed. Number andlength of the separating sections are selected in accordance with therange of parcel lengths and the rated transport speed so that subsequentparcel located at the minimum gap distance is not yet located in theupstream rearmost stopped separating section. The drive of each stoppedseparating section is started again as soon as the rear edge of thepreceding parcel has left this separating section in each case or assoon as the subsequent parcel in each case is located just before a freeseparating section.

The stop/start process of the separating sections for transporting thepreceding parcel thus does not influence the transport of the subsequentparcel in the separating distance, which then without interruption andload moves with a small gap from the preceding parcel up to thereception point.

Advantageous embodiments of the invention are set down in the subclaims.

To maintain the minimum, i.e. the optimum gap between the parcels, it isadvantageous for the short parcels for the gap from the midpoint of thedownstream rear deflection rollers of the transport belts from theseparating section at the reception point of this corresponds to theminimum parcel length minus the minimum gap between the parcels minusthe distance covered by the parcels on braking from the relevant ratedspeed to the value 0 or on acceleration from standstill to the ratedspeed.

So that the subsequent parcels can follow the previous parcels at aminimum distance it is advantageous, if upstream from the separatingsection at the reception point at least one separating section isarranged, for which the distance of the center points of the deflectionrollers of the transport belts on the transport path corresponds to theminimum gap between the parcels minus the distance covered by theparcels on braking from the relevant rated speed to the value 0 or onacceleration from standstill to the relevant rated speed. The gapsbetween the centers of the deflection rollers of the transport belts ofthese transport sections from the adjacent deflection rollers of theadjacent transport sections correspond in this case at least to thedistance which the parcels cover on braking from the relevant ratedspeed to the value 0 or on acceleration from standstill to the relevantrated speed, but at their maximum are not greater than the minimumparcel length.

To maintain the minimum, i.e. the optimum gap between the parcels evenwith long parcels, it is advantageous for the gap between the centerpoints of the deflection rollers of the separating sections arrangedupstream adjoining the separating section(s) downstream, of which thedeflection rollers on the transport path are spaced from each other bythe value of the minimum gap between the parcels minus the distancewhich the parcels cover when braking from the relevant rated speed tothe value 0 or on acceleration from standstill to the relevant ratedspeed, from the reception point correspond to at least the length of thelongest parcel minus the minimum gap reduced by the braking oracceleration distance between the parcels.

The invention is explained below in an exemplary embodiment withreference to the drawing.

The FIGURE shows

FIG. 1 a schematic overhead view of the rear part of the separatingdistance.

A multistage separating device consist of an input area not shown inwhich stacks of vertical parcels are fed automatically to firstseparating units, e.g. vacuum-assisted extraction belts on which thefrontmost parcels are drawn off in each case and then fed to furtherseparating sections 12-13 c of a separating distance. This is necessarysince the parcels are frequently located, sometimes deliberately, at thestart of the separating distance in overlapped form as an overlappingflow of parcels and parcel flow is then to be resolved into individualparcels moved with gaps between them. Fixed retaining elements can bearranged on the side opposite the removal or transport belt. Theseretaining elements are however frequently not in a position tocompletely resolve the overlapped flow. In FIG. 1 the rear part of theseparating distance is shown in an overhead view, with the retainingelements lying opposite the separating elements on the transport pathnot being shown for reasons of clarity.

Individually-supported deflection rollers 2 of the transport belts 3,which are driven in the separating sections 12,13 a in each case by adrive motor 4.1, 4.2, are mounted between the two separating sections 13a on a common shaft 1. The transfer gap in the flow of the verticalparcels which are standing in the transport path on an underfloor beltnot shown to support transport is reduced in this way to 0 mm. Thearrangement allows an absolutely impact-free parcel transfer to thesubsequent separating section 13 a.

The different-height, preferably alternating arrangement of thetransport belts 3 in the separating sections 12, 13 a means that theretaining elements acting between the transport belts 3 must changetheir vertical positions. Parcels 8, 9, which have hooked onto holes orfastenings in each other, i.e. multiple removals, can, as a result ofthe different gripping points of the retaining elements on the parcels8, 9, be released from each other more easily.

If the belt transport is to be additionally assisted by vacuum,statically arranged vacuum chambers 7 of the accepting separatingsections 12-13 c in each case are advantageously arranged close to thetransition from the previous separating section. The parcel 8,9 to beaccelerated is pulled at an early stage in the next upstream separatingsection by its vacuum chamber 7 onto its transport belt 3 so that thecarrying force is increased.

Each next upstream separating section has a higher transport speed inrelation to the preceding separating section, which provides additionalsupport for the separating process.

An array of sensors 11 with individual light barriers 11 a-d is arrangedalong the transport path, with which the positions of the front and/orrear edges of the parcels 8,9 for triggering switching signals for thedrive motors are identified.

So that the parcels 8,9 are transferred with few difficulties into thereception point 10, clamped between transfer rollers 6, of which theopposing rollers are not shown, the transfer rollers 6 are arranged sothat they can rotate jointly on a shaft with the rear deflection rollers2 of the last separating section 13 c. So that the parcels aretransported in the separating distance with small gaps in the mostprotected manner possible, operation is set up so that each subsequentparcel 8,9 is transported without interruption at least through theupstream part of the transport path up to the reception point. In thisprocess however overlaps of the parcels are also to be resolved wherepossible. For this reason the first parcel is transported through theseparating sections 13 a-c to parcel reception point 10 withoutstopping. As soon as the light barrier 11 d positioned directly over theclamping point of the parcel transfer 10 is darkened by the front edgeof the parcel. the parcel 8,9 is gripped by the rollers of the receptionpoint 10 and all separating sections 13 a-c in which the first parcel islocated are stopped (this is the separating section 13 c for the shortparcel 9, for longer parcels in addition the separating section 13 b aswell and for a very long parcel 8 also the separating section 13 a too).The first parcel is now drawn out by the transfer rollers 6 of thereception point 10 against stationary transport belt 3. Theseadditionally act as retaining elements on the parcel transport side onany double withdrawal which might occur.

Number, gaps and lengths of the separating sections 13 a-c are selectedso that the subsequent parcel with “minimum gap” distance in each caseis not yet located in one of the stopped separating sections 13. In thisexample, in relation to the shortest and the longest parcel 9,8, thismeans: The distance between center points of the deflection rollers 2 ofthe separating sections 13 c located on the transport path at thereception point 10 corresponds to the length of the shortest parcel 9minus the minimum gap between the parcels 8,9 minus the acceleration orbraking distance which is necessary to bring a parcel 8,9 fromstandstill up to the relevant rated speed or from the rated speed to astandstill. Before this there is a separating section 13 b, of which thecenter points of the deflection rollers 2 on the transport path are at adistance of the value of the minimum parcel gap minus theacceleration/braking distance from each other. The center points ofthese deflection rollers 2 are at a distance from the center points ofthe adjacent deflection rollers 2 of the adjacent separating sections 13a, 13 c of at least the amount of the acceleration/braking distance. Thedistance between the center points of these deflection rollers 2 musthowever also be smaller than the length of the shortest parcel 9 toensure its safe transport.

If the front edge of the longest parcel 8 has reached the receptionpoint 10, the distance from the rear edge to the center point of therear deflection roller 2 on the transport path of the separatingsections 13 a is the amount of the minimum parcel gap minus theacceleration/braking distance.

If the difference between the shortest and the longest parcel 9,8 isgreater, a number of separating sections, for which the distance betweenthe center points 1 of the deflection rollers 2 on the transport is theamount of the minimum parcel gap minus the acceleration brakingdistance, are arranged after one another.

As soon as the rear edge of the preceding parcel leaves the relevantseparating sections 13 a-c, which is detected by the light curtains 11a-d the drive motors 4.2 to 4.5 of the relevant separating sections arestarted again to transport the subsequent parcel i.e. this enters movingseparating sections. The drive motors 4.2 to 4.5 ca also be started assoon as the subsequent parcel 8, 9 is located shortly before a freeseparating section 13 a, 13 b, 13 c.

If the start of the resolution of overlapping is determined by the factthat the rear edge of the previous parcel is moving more slowly than thetransfer rollers 6 of the reception point 10, and if this resolution issuccessful before the parcel transfer, the gap between the front edge ofthe rear parcel of the overlap and the rear edge of the front parcel ofthe overlap is monitored with the aid of a timer unit (in the drivemotor 4.5 of the transfer rollers 6) and the sensor array 11. When therequired gap is achieved the separating sections 13 a, 13 b and 13 c arestarted again.

If the overlap is not separated before transfer of the parcel in thereception point 10, a double withdrawal is occurring. As soon as therear edge of the overlap has then reached the reception point 10, theseparating sections 13 a, 13 b and 13 c are started again.

1.-4. (canceled)
 5. An apparatus for separating overlapping flat parcelsin a vertical position, comprising: a number of separately-drivenseparating sections arranged along a transport path immediately behindone another; and a drive controller for the separating sections, whereineach separating section comprises: transport belts for transportingparcels, a retaining element at a height between the transport belts andoperating with frictional force on the parcels, and an array of sensorsarranged along the transport path and configured to detect front andrear edges of the parcels, wherein separated parcels are acceptedclamped into a transport means and removed from the separating distanceat a reception point at a downstream flow end of the separatingapparatus, wherein the drive controller comprises a drive motor for eachseparating section, and is configured so that the drive motor of thoseseparating sections, in which a frontmost downstream parcel is located,is immediately stopped as soon as its front edge is detected in thereception point, wherein number and length of the separating sectionsare selected in accordance with a range of lengths of the parcels andrated transport speeds so that a subsequent parcel spaced at a minimumgap in each case is not yet located in a rearmost downstream stoppedseparating section, and wherein the drive motor of each stoppedseparating section is restarted as soon as a rear edge of a previousparcel in each case has left a current separating section or as soon asthe subsequent parcel in each case is located before a free separatingsection.
 6. The separating apparatus of claim 5, wherein downstream reardeflection rollers of the transport belt have a center point, wherein adistance between the center point and a separating section upstream fromit to the reception point corresponds to a minimum parcel length plus aminimum gap between the parcels minus a distance, which the parcelscover during braking from the relevant rated speed to a standstill, orone acceleration from standstill to the relevant rated speed.
 7. Theseparating apparatus of claim 5, wherein deflection rollers of thetransport belts have a center point, wherein upstream from theseparating sections at the reception point at least one separatingsection is arranged, for which a distance of the center pointscorresponds to a minimum gap between the parcels minus a distancecovered by the parcels on braking from the relevant rated speed tostandstill or on acceleration from standstill to the relevant ratedspeed, and distances of the center points of these separating sectionsfrom adjacent deflection rollers of adjacent separating sections atleast correspond to a distance which the parcels cover on braking fromthe relevant rated speed to standstill or on acceleration fromstandstill to the relevant rated speed, but at a maximum are not greaterthan the minimum parcel length.
 8. The separating apparatus of claim 5,wherein downstream rear deflection rollers of the transport belts have acenter point, wherein a distance between the center points of thedeflection rollers arranged upstream of the separating sections adjacentdownstream to the separating sections of their deflection rollers on thetransport path corresponds to an amount of a minimum gap by which theparcels are spaced from one another, minus a distance covered by theparcels on braking from the relevant rated speed to standstill or onacceleration from standstill to the relevant rated speed from thereception point at least the length of a longest parcels minus a minimumgap between the parcels reduced by the braking or acceleration distance.